U.S. patent application number 10/235510 was filed with the patent office on 2003-03-13 for electronic sign for information equipped for satellite positioning system on passenger transportation vehicle.
Invention is credited to Saraiva, Pablo Salle.
Application Number | 20030050744 10/235510 |
Document ID | / |
Family ID | 26928977 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030050744 |
Kind Code |
A1 |
Saraiva, Pablo Salle |
March 13, 2003 |
Electronic sign for information equipped for satellite positioning
system on passenger transportation vehicle
Abstract
A system which includes an electronic sign located in a vehicle
of a passenger transportation system with the capability of showing
letters, numbers and graphs. The electronic sign is equipped with a
satellite based positioning system which enables specific
information uploading for a particular geographical region for
displaying information, news, publicity, advertisement, and
services for the passenger. The electronic sign capability of
determining its position allows it to locate the appropriate
"uploading sites," which automatically update information for the
geographic position where the information should be addressed for
any number of signs located in that geographic position. This makes
it simple to advertise or inform the nearby population in a
previously chosen target region.
Inventors: |
Saraiva, Pablo Salle; (La
Teste, FR) |
Correspondence
Address: |
Richard C. Litman
LITMAN LAW OFFICES, LTD.
P.O. Box 15035
Arlington
VA
22215
US
|
Family ID: |
26928977 |
Appl. No.: |
10/235510 |
Filed: |
September 6, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60317490 |
Sep 7, 2001 |
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Current U.S.
Class: |
701/1 ;
340/425.5 |
Current CPC
Class: |
G08G 1/0962
20130101 |
Class at
Publication: |
701/1 ;
340/425.5 |
International
Class: |
G06F 017/00 |
Claims
I claim:
1. An electronic sign for installation in a passenger vehicle
comprising: a radio receiver; a satellite positioning system unit;
a central processing unit; a data memory; an electronic screen; and
a radio receiver/transmitter; whereby said radio receiver receives
a particular update signal as determined by said satellite
positioning system unit, said signal being processed by said
central processing unit and stored in said data memory for updating
said data memory; whereby said data memory provides updated
information to said electronic screen for presentation thereon; and
whereby said data memory provides updated information to said radio
transmitter, and thus said radio transmitter, for transmitting said
update signal.
2. A system for providing updated information to a passenger
vehicle comprising: an uploading site having means for transmitting
an update radio signal; at least a first and a second vehicle
mounted electronic sign, each said sign having: means for receiving
an update radio signal; means for storing update signals to form an
updated database; means to display said updated database; and means
to transmit said updated database as a radio signal; whereby at
least one of said first vehicle mounted electronic signs receives
said update signal from said uploading site; and whereby at least
one of said second vehicle mounted electronic signs receives said
updated database radio signal from said at least one first
electronic sign.
3. A method of providing updated information to the public in at
least first and second vehicles comprising; providing an uploading
site having means for transmitting an update radio signal;
providing at least a first and a second electronic sign
corresponding to said first and second vehicles, each said sign
having: means for receiving an update radio signal; means to
display said updated database to a vehicle passenger; and means to
transmit said updated database as a radio signal; said uploading
site sending an upload radio signal to said at least first
electronic sign; said at least first electronic sign displaying
data to said passengers in said first vehicle received from said
uploading site by means of said upload radio signal; said at least
first electronic sign sending an upload radio signal to said at
least second electronic sign; and said at least second electronic
sign storing the same data stored on said at least first electronic
sign to said passengers in said second vehicle according to said at
least second electronic sign position.
4. An electronic sign for information located on a vehicle of
passenger transportation systems utilizing a satellite positioning
system receiver in combination with a dynamic electronic sign, said
sign for installation in a said vehicle of a said passenger
transportation system comprising: a satellite positioning system
receiver; a central processing unit; a data memory; an electronic
screen; and a radio receiver/transmitter; whereby the installation
of said satellite positioning system receiver combined with said
dynamic electronic sign on said passenger transportation system
unit creates an environment of great versatility for information,
publicity, advertisement and services; whereby said central
processing unit, utilizing said radio receiver/transmitter,
receives data through a radio frequency signal from a specific
fixed uploading site; whereby said fixed uploading site is
accurately located by said satellite positioning system receiver.
whereby said central processing unit, utilizing said radio
receiver/transmitter may receive data through radio frequency
signal from another identical electronic sign mounted in another
vehicle; whereby said radio receiver/transmitter of said sign and
said radio receiver/transmitter of said another identical
electronic sign mounted in another vehicle run spread-spectrum with
the same noise code; whereby the entire electronic sign system is
synchronized with said satellite positioning system; said fixed
uploading site comprising: a modem connected to a telephone line; a
satellite positioning system receiver; a central processing unit; a
data memory; a radio receiver/transmitter; means for receiving new
information through said modem; means for processing said new
information by its said central processing unit; and means for
storing said new information in its said data memory; whereby said
new information received through radio frequency by said central
processing unit of said electronic sign is verified and stored in
said data memory of said electronic sign; whereby said new
information updates existing data stored at said data memory of
said electronic sign; whereby said updated data stored in said data
memory of said electronic sign have the information to be displayed
at said electronic screen and the coordinates(longitude, latitude)
of where said information should be displayed; whereby said central
processing unit of said electronic sign receives said
coordinates(longitude, latitude) from said satellite positioning
system receiver of said electronic sign; and whereby, according to
said coordinates (latitude, longitude) and said data stored in said
data memory, said central processing unit updates information to be
displayed at said electronic screen; thus creating an environment
of great versatility for information, publicity, advertisement and
services.
5. The electronic sign of claim 4, further comprising means for
changing information versus time at the same geographic
position.
6. A system for providing updated information to a vehicle of a
passenger transportation system, according to claim 5, comprising:
a fixed uploading site; at least one vehicle mounted electronic
sign; said fixed uploading site having: means for transmitting
updated information, through a radio signal, to said at least one
vehicle mounted electronic sign; said at least one vehicle mounted
electronic sign having: means for locating the position of said
fixed uploading site through said satellite positioning system
receiver of said at least one vehicle mounted sign; means for
receiving a radio signal from said fixed uploading site; and means
for storing updated information in said data memory of said at
least one vehicle mounted electronic sign.
7. A system for providing updated information to a vehicle of a
passenger transportation system according to claim 6, comprising;
at least one vehicle mounted electronic sign, said sign having;
means for locating its position through its satellite position
receiver; and means to display updated information according to the
said sign position.
8. The system of claim 7, further comprising at least one fixed
ground retransmission base for installation in an obstacle rich
environment comprising; a satellite position system receiver; a
radio receiver/transmitter; a central processing unit; a modem
connected to a telephone line; a data memory; means for maintaining
synchronization with satellites through said satellite positioning
receiver of the said retransmission base; means for determining the
position of at least one vehicle mounted electronic sign through
signals emitted from said radio transmitter of said retransmission
base and received by said radio receiver/transmitter of said
vehicle mounted electronic sign; whereby the location of said
electronic sign is determined in case and obstacle occurs between
said electronic sign and a satellite rendering the number of
satellites insufficient for said electronic sign position
calculation; whereby said retransmission base utilizes noise code
different from the noise code utilized by the satellite positioning
system, allowing said radio receiver/transmitter of said electronic
sign to recognize transmissions received from said radio
transmitter of said retransmission base; whereby the
position(coordinates) of said retransmission base is accurately
known; whereby said radio receiver/transmitter of said
retransmission base emits its position within spread-spectrum
utilizing PRN code in the manner of the satellites and emits its
carrier signal synchronized with said satellites; and whereby
allowing said radio receiver of said electronic sign, located
within the said radio transmitter range of said base, to recognize
the said transmitter through its PRN code and to calculate the
radio receiver position utilizing said base as an additional
satellite.
9. The system of claim 8, further comprising means for updating
said data memory of said retransmission base through said modem
connected to said telephone line of said retransmission base.
10. A method of employing the system of claim 9 to provide updated
information to the public in at least first and second vehicles
comprising the steps of: providing a fixed uploading site;
providing at least a first and second electronic sign corresponding
to said first and second vehicle; transmitting updated information
by radio signal from said fixed uploading site; said sign receiving
updated information through radio signal; said sign displaying
updated information in its electronic screen; said sign
transmitting said updated information through radio signal
synchronized with its satellite positioning system receiver;
sending updated information from said fixed uploading site, through
radio signal, to said at least first electronic sign; said at least
first electronic sign displaying in its electronic screen
information to said first vehicle according to the said at least
first vehicle position; said at least first electronic sign
uploading by radio signal the said second electric sign with
information stored in the said first sign memory; said at least
second electronic sign storing said information in its data memory;
said at least second electronic sign displaying its electronic
screen information to said second vehicle according to said second
vehicle position; and whereby said received information by radio
signal from said at least first electronic sign increases the
capability for updating information outside the reach of an
uploading site.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Serial No. 60/317,490, filed Sep. 7, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to electronic displays for use
in vehicles. More particularly, the present invention relates to an
electronic display sign and screen which is updated by radio
transmitters according to its location as determined by a satellite
positioning system located within the vehicle.
[0004] 2. Description of Related Art
[0005] Electronic signs located in passenger vehicles with the
capability of being uploaded from a computer or from an infrared
remote control are known. They were built for delivering individual
messages, but they are not equipped with satellite positioning
systems, therefore, they cannot be geographically positioned. It
would be desirable to have a vehicle system in a transportation
system which may be updated according to its position, may deliver
visual media for passengers, have capability to pass update
information between similarly equipped vehicles, even in case an
obstacle occurs, i.e., satellites are not visible for vehicle
positioning.
[0006] U.S. Pat. No. 5,627,549, issued May 6, 1997 to Park
describes a vehicle information device equipped with a GPS receiver
and a radio receiver. The device receives advertisements and map
information over the radio. It displays this information to the
user but also stores it so that the user can access it in greater
detail at a later time. The device receives data transmission from
a station relating to an advertisement as heard on the vehicle
radio and calculates and displays directions to the advertiser.
[0007] U.S. Pat. No. 6,185,501 B1, issued Feb. 6, 2001, to Smith et
al. describes a system in which navigation information,
advertisements, and messages specific to the occupants of a vehicle
are delivered to an information device inside the vehicle. The
delivery of this information occurs while the vehicle is at a gas
station, rest stop, or tourist center.
[0008] U.S. Pat. No. 6,154,689, issued Nov. 28, 2000, to Pereira et
al. describes a multimedia system equipped with a GPS Receiver for
use in vehicles. Based on the geographic position of the vehicle,
the device displays entertainment programs or travel
information.
[0009] Uruguayan Patent No. 13,742, published Aug. 8, 1997 and
granted Nov. 15, 1999, to Salle Saraiva, the present inventor, is
related to the present invention and describes an electronic sign
system over which the present invention is an improvement.
[0010] None of the above inventions and patents, taken either
singly or in combination, is seen to describe the instant invention
as claimed.
SUMMARY OF THE INVENTION
[0011] The present invention is a system which includes an
electronic sign located in a passenger vehicle or each of a fleet
of vehicles, such as a city bus system, with the capability of
showing letters, numbers and graphs to a passengers such as the
public traveling on the bus system. The electronic sign is equipped
with a satellite based positioning system which enables specific
information uploading for a particular geographical region for
displaying relevant information, news, publicity, advertisement,
and services for the passenger. The electronic sign capability of
determining its position allows it to locate the appropriate
"uploading sites," which automatically update information relevant
for the geographic position where the information should be
addressed for any number of signs located in that geographic
position. Besides, the electronic sign has the capability of
changing information versus time for a set geographic position.
This makes it simple to advertise or inform the nearby population
in a previously chosen target region.
[0012] Any electronic sign located within the transmitter zone
reach can be uploaded through radio frequency with a low power
transmitter, avoiding the high cost of a medium power transmitter
as well as resultant radio frequency pollution. The only units
uploaded are the ones located within the transmitter reach and
programmed to receive its data at that position. The inventive
system allows the delivery of selected publicity from the
electronic sign screen to consumers, since the advertisement can be
changed according to the geographic position of the unit. The
inventive system also allows for the release of information(such as
news headlines, game scores, etc.) because each sign can be
uploaded at any time. The inventive system also allows the release
of information related to the passenger's immediate interest, such
as next stop, exact time, and so forth.
[0013] The system in the passenger vehicle includes an electronic
sign with an electronic screen, central processing unit, data
memory, radio receiver, and satellite positioning system unit. It
also includes a radio transmitter operating at the same frequency
as the transmitters at uploading sites and running with spread
spectrum but different noise code (diphase modulation) in
comparison to the transmitters at uploading sites. For a number of
vehicles having the inventive system, their signs are time
synchronized by the satellite positioning system receiver. Thus, a
dialog time can be associated to each electronic sign in a way that
one sign can receive new information from another sign in another
vehicle, eliminating the need of being close to an uploading site.
In this manner a communication network is established within a
vehicle fleet equipped with the electronic sign system and the
uploading site.
[0014] The uploading site includes a modem, a central processing
unit, a data memory, a transmitter with radio frequency operating
at spread spectrum, but noise code(diphase modulation) different
from the transmitters located on the electronic signs described
above, and a positioning satellite system receiver. Transmitters of
uploading sites are synchronized by satellite positioning system
receivers, so that transmitters can be utilized for a position
calculation system which are needed in the case of a hidden
satellite situation or occurrence of reflected signals due to
occasional obstructions during the vehicle trajectory related to
its geographical position, thus substituting the hidden satellite
for position calculation.
[0015] Each electronic sign has two operational modes: a mode for
information on screen, and a mode for uploading.
[0016] In the information on screen mode, the electronic sign
central processing unit(CPU) determines its position using its
internal satellite positioning system receiver. Thus, according to
its position, it automatically runs messages stored in its data
memory such as publicity, advertisements, news, next vehicle stop
and so forth. Within this mode, an electronic sign installed on a
vehicle has the ability of communicating through radio
frequency(utilizing its transmitter and receiver) with other
vehicles(through their signs) located in its proximity and
synchronized with their respective satellite positioning system
receivers installed on each vehicle. Their communication becomes
automatically synchronized and, in this way, new information can be
interchanged at will. Also, information update becomes
instantaneous, since there is no need for a vehicle to approach an
uploading zone to be uploaded. All vehicles have the ability to
upload each other with updated information, forming a communication
network within the vehicle fleet. Therefore, there is no need of
multiple uploading zones for information update.
[0017] Whenever the central processing unit of an electronic sign
detects, through its positioning satellite system receiver, that it
is within the reach of an uploading zone, it automatically switches
to uploading mode. Newly received information is automatically
stored in its data memory. Information is updated whenever an
electronic sign is located within an uploading site reach.
[0018] The uploading site is connected through telephone line to
upload new data to be processed by electronic signs. Through a
modem connected to the telephone line, a microprocessor receives
and stores data in its memory. The communication automatically ends
after data are transferred, allowing data to be automatically
resent to the transmitter. These data are thereby sent to and
received by every electronic sign equipped with a satellite
positioning system receiver which is located within the uploading
zone.
[0019] The transmitter and the satellite positioning system
receiver of the uploading site are synchronized, and are accurately
located, allowing their utilization for calculating a vehicle
position in a site where uploads are received, but not enough
satellites are in line of sight.
[0020] Accordingly, it is a principal object of the invention to
provide an electronic sign for displaying information on
transportation systems such as a fleet of vehicles which utilizes a
satellite position unit in combination with dynamic signs, creating
an environment of great versatility for the dissemination of
information, publicity, advertisement and services.
[0021] It is another object of the invention to provide an
electronic sign system as above which is uploaded utilizing a
satellite positioning system unit that allows sending and changing
of data from fixed sites.
[0022] It is a further object of the invention to provide an
electronic sign system as above having the ability to change
displayed data at will, according to the vehicle geographical
location as obtained through its satellite positioning system
receiver.
[0023] Still another object of the invention is to provide an
electronic sign system as above which utilizes transmitters
synchronized with the vehicle satellite positioning system receiver
for calculating its position, thus, substituting the satellite in
case an obstacle occurs between the electronic sign satellite
positioning receiver antenna and the satellite or reflected signals
are received, allowing the system to change display information
automatically according to the vehicle's geographical location by
means of its satellite positioning system receiver.
[0024] It is yet another object of the invention to provide an
electronic sign system as above wherein the transmitters in the
vehicles are synchronized with the satellite positioning system
receiver of a vehicle's electronic sign so that information may be
interchanged with all remaining vehicles, thus increasing their
capability to update information when outside the reach of an
uploading site.
[0025] It is an object of the invention to provide improved
elements and arrangements thereof in apparatuses for the purposes
described which is dependable and fully effective in accomplishing
their intended purposes.
[0026] These and other objects of the present invention will become
readily apparent upon further review of the following specification
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a diagrammatic representation of the electronic
sign system for vehicles according to the present invention.
[0028] FIG. 2 is a diagrammatic representation of the electronic
sign system of FIG. 1 illustrating communication between signs in
separate vehicles, a satellite, and a fixed upload station.
[0029] FIG. 3 is a diagrammatic representation similar to that of
FIG. 2 with the addition of fixed retransmission base sites for use
in obstacle rich environments such as cities.
[0030] Similar reference characters denote corresponding features
consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] The present invention includes an electronic sign located in
a passenger vehicle with the capability of showing letters, numbers
and graphs. The electronic sign is equipped with a satellite
positioning system which enables easy uploading and providing
capability for displaying relevant information, news, publicity,
advertisement, and services for the passenger. The electronic sign
capability of determining its position allows it to locate
"uploading sites." These sites automatically update any number of
signs within a geographic region with information intended for
signs in that geographic region. This makes it simple to advertise
or inform the nearby population in a previously chosen region.
[0032] The system in the passenger vehicle includes an electronic
sign with a central processing unit, data memory, radio receiver,
and satellite positioning system unit. It also includes a radio
transmitter operating at the same frequency as the transmitters at
uploading sites and running with spread spectrum but different
noise code(diphase modulation) in comparison to the transmitters at
uploading sites. For a number of vehicles having the inventive
system, their signs are time synchronized by the satellite
positioning system receiver. Thus, a dialog time can be associated
to each electronic sign in a way that one sign can receive new
information from another sign in another vehicle, eliminating the
need of being close to an uploading site. In this manner a
communication network is established within a vehicle fleet
equipped with the electronic sign system and the uploading
site.
[0033] The uploading site is connected through telephone line to
upload new data to be processed by electronic signs. Through a
modem connected to the telephone line, a microprocessor receives
and stores data in its memory. The communication automatically ends
after data are transferred, allowing data to be automatically
resent to the transmitter. These data are thereby sent and received
by every electronic sign equipped with satellite positioning system
receiver located within the uploading zone.
[0034] Referring to FIGS. 1 and 2, there are shown diagrammatic
representations of the inventive electronic sign system 10. Sign
system 10 includes vehicle mounted sign 12 having an electronic
screen 14, a central processing unit(CPU) 16, a data memory 18, a
radio frequency receiver/transmitter 20, an antenna 22 for
reception and sending of radio frequency signals, and a satellite
positioning receiver 26 having satellite receiver antenna 28 for
receiving positioning data from satellite S.
[0035] Electronic sign system 10 also includes fixed uploading site
40, having fixed site CPU 42, telephone line 44, fixed uploading
site telephone communication modem 46, fixed uploading site data
memory 48, fixed uploading site radio transmitter 50, antenna 52
for transmitting radio frequency signals to said vehicle antenna
22, and satellite receiver antenna 54 and satellite positioning
receiver 56 for receiving positioning satellite data from satellite
S.
[0036] As seen in FIG. 2, two signs 12, having electronic screens
14, and mounted on two vehicles(not shown), have
transmitter/receiver antenna 22, and satellite positioning system
receiver antenna 28. Radio transmitter 20 and antenna 22 (see FIG.
1) operate at the same frequency as the transmitters 50 and antenna
52 at uploading sites 40, operating with spread spectrum, but with
different noise code (diphase modulation) in comparison to the
transmitters 50 at uploading sites. Synchronization of each
electronic sign 12 is effected via their respective satellite
positioning system antennae 28, i.e., all electronic signs are
synchronized. Thus, a dialog time can be associated with each
electronic sign 12 in a known manner such that one sign may receive
new information from another via their respective
transmitter/receiver antenna 22, eliminating the need of all signs
being close to an uploading site. A communication network is
thereby established within the vehicle fleet equipped with the
vehicle mounted signs 12 as well as with their uploading site
40.
[0037] The uploading site 40 includes transmitter 50 with radio
frequency operating at expanded spectrum but noise code(diphase
modulation) different from the transmitters located on the
electronic signs. Uploading site 40 also includes a positioning
satellite system receiver 56. Transmitters 50 of uploading sites 40
are synchronized with satellite position system receivers 12 of
vehicle mounted signs so that transmitters can be utilized for a
position calculation system (not shown). This position calculation
system is used in the case of hidden satellite situations or
occurrence of reflected signals due to occasional obstructions
during the vehicle trajectory related to its geographical position
as further explained below.
[0038] In operation, each electronic sign has two operational
modes. During the operational mode for information on screen, the
electronic sign CPU 16 determines its position using data from the
internal satellite position system receiver 26. Then, according to
its position, it automatically runs messages stored in its data
memory 18 such as publicity, advertisements, news, next vehicle
stop, etc.
[0039] Within this mode, an electronic sign 12 installed on a
vehicle has the ability of communicating through radio frequency
signal (utilizing its receiver/transmitter 20) with other vehicles
(through their electronic signs 12) located in its proximity and
synchronized by means of their respective satellite positioning
system receiver 26 as installed in both vehicles. Their
communication is automatically synchronized and, in this way, new
information can be interchanged at will. Also, information update
becomes instantaneous, since there is no need for a vehicle to
approach an uploading site to be uploaded. All vehicles have the
ability to upload each other with updated information, forming a
communication network within the vehicle fleet. Therefore, there is
no need of multiple uploading sites for information update.
[0040] Whenever the electronic sign CPU 16 detects, through its
positioning satellite system receiver 26, that it is within the
reach of an uploading site 40, it automatically switches to
uploading mode. Newly received data is automatically stored in its
data memory 18. Data is updated whenever an electronic sign 12 is
located within an uploading site reach.
[0041] The uploading site 40 is connected with telephone line 44 to
upload new data to be processed by electronic signs 12 by means of
a modem 46 connected to the telephone line 44. The data is then
received by a data processing CPU 42 and stored in fixed site data
memory 48. This communication automatically ends after data are
transferred, allowing data to be automatically resent to the fixed
site radio transmitter 50. These data are sent and received by
every electronic sign 12 within the uploading zone.
[0042] The transmitter 50 and the satellite positioning system
receiver 56 of the uploading site 40 are synchronized with each
other, and are accurately located, allowing their utilization for
calculating a vehicle position in a zone where uploads are
received, but insufficient satellites are in the vehicle line of
sight.
[0043] Referring to FIG. 3, there is shown a system similar to that
of FIG. 1 with the addition of fixed ground transmitter sites 60.
Sites 60 include radio receiver/transmitter 62 having
receiver/transmitter antenna 64, and satellite positioning system
receiver 66 having antenna 68. Sites 60 are useful in obstacle rich
environments as explained below. They have a known fixed location
and incorporate a ground radio receiver/transmitter 62 with
receiver/transmitter antenna 64 and a satellite positioning system
receiver 66 having antenna 68. Ground radio transmitter 62 and
satellite positioning receiver 66 are synchronized with each other.
They assume the function of a satellite which may not be in the
direct view of the vehicle sign 12 to assist in determining the
location of the vehicle sign. With the addition of a radio
receiver, a central processing unit, a data memory, and a modem
connected to a telephone line (none of these shown), they become
capable to retransmit upload information as an uploading site.
[0044] The system functions based upon utilization of a satellite
group, where satellites emit modulated (phase) carrier signals. The
phase of satellite signals is synchronized through atomic clocks.
Each signal is modulated (phase) by noise code (PRN) resulting in a
spread-spectrum signal. The receiver position is calculated through
the difference in phase of signals from satellites to receiver
(calculation by code). The measurement of the difference in phase
of satellite signals determines the difference in distance traveled
by the signals, which is (in first approach) proportional to the
difference of distances between the receiver and the satellites.
The antenna receiver position is determined by mathematics
calculation in a known manner, utilizing the known satellites'
positions.
[0045] Problems to overcome in practice include the fact that
positioning satellite receivers malfunction in an urban environment
in those cases where obstacles are present between their antennae
and the satellites. Three visible satellites are needed for
calculating the receiver position. In the case where the receiver
is located in a zone within obstacles (buildings for instance) the
required number of satellites may not be visible, or signals from
the satellites might be reflected, therefore introducing error.
[0046] A solution to overcome the above-mentioned problems
according to the present invention includes the utilization of
ground transmitters 60 as a substitute for satellites that are not
in view of the receiver vehicle. The transmitter at an upload site
may act as one transmitter as mentioned above. The utilization of a
ground transmitter clock, synchronized with the satellites' clocks
insure the satellites' clock precision-relative to the transmitter
clock. Transmitters are strategically located within all critical
zones of reception. The transmitters may also be utilized as
digital data retransmission bases for information updating. For
each retransmission base, one satellite receiver is installed,
capable of synchronizing its clock with that of the satellites.
Each base location (coordinates) has been accurately positioned and
is known. The utilization of a noise code different from the noise
code utilized by the satellite system allows the identification of
a signal transmission received from a ground transmitter. By this
means, the transmitter emits its position within the spread
spectrum, utilizing PRN code in the manner of the satellites. Also,
the transmitter emits its carrier signal synchronized with the
satellites. This procedure allows a receiver located within the
transmitter range to recognize the transmitter through its PRN code
and to calculate the receiver's position utilizing the base as an
additional satellite.
EXAMPLE
[0047] For utilization in a public transportation system in an
urban environment, the electronic system comprises a central
office, fixed uploading sites and electronic signs installed on
buses, and transmitter bases.
[0048] The central office is equipped with a PC, and modem
connected to a telephone line.
[0049] Fixed uploading sites are equipped with radio
receiver/transmitter, modem connected to telephone line, CPU, data
memory and satellite positioning receiver, and may be located at
bus terminals.
[0050] Electronic signs installed on buses are equipped with
electronic screen, CPU, data memory, radio receiver/transmitter,
and satellite positioning receiver.
[0051] Transmitter bases are equipped with satellite positioning
receiver and radio transmitter, and strategically located for
calculating electronic sign(bus) position as a substitute for
satellites in the case where obstacles(buildings) are present
between the electronic sign satellite positioning receiver antenna
and the satellites. Such bases may be installed in addition to a
fixed uploading site. A retransmission base may optionally be
furnished with additional equipment to have uploading site features
added to it (additional equipment identical to that of an uploading
site).
[0052] An uploading site is connected to the central office through
a telephone line to upload new data to be processed by electronic
signs, which release advertisement, publicity, news, and
information through their electronic screens. An advertisement is
delivered to bus passengers according to the bus position, i.e., an
advertisement for a business nearby the bus position is delivered
to passengers whenever the bus approaches the business location. By
these means, a large number of advertisements combined with new and
information can be delivered to bus passengers. The electronic
screen becomes an entertainment to bus passengers and the
advertisement becomes affordable for small business.
[0053] An electronic sign has means for precisely determining its
specific uploading site for receiving its specific data, whether
there is another uploading site nearby or not. As an example, two
uploading sites located in the same bus terminal for delivering
different data to two different bus lines, respectively.
[0054] An electronic sign mounted on a bus also has means for
uploading another similar sign, and recognizes all signs where
upload is addressed. This capability is useful, for example, in the
situation where new information should be interchanged among buses
of the same line only. Therefore, buses of different lines equipped
with signs will not interchange information, even if they approach
on another. In this manner, according to this example, buses of the
same line can upload new information among them outside the reach
of an uploading site, thus allowing faster information update, and
forming a communication network within buses of the same line
equipped with electronic signs for viewing by members of the public
traveling on the buses.
[0055] It is to be understood that the present invention is not
limited to the sole embodiment described above, but encompasses any
and all embodiments within the scope of the following claims.
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